The Department of Biological Sciences at the University of Denver requests support to purchase an electron microscope from the Shared Instrumentation Program. The instrument is needed by 5 members of this department for research in the following areas of biology: 1). Processing of pro-opiomelancortins. These products will be studied with colloidal gold antibody localization as a model system for polypeptide sorting in the GERL. 2). Identification of microorganisms, phage infection, and lipid bodies in the cactus system. This study represents a unique microcosm in a multi-tiered study of cellular regulation of population biology and evolution. 3). The effect of B-lympho-blastoid stimulatory vesicles on modulators of the immune proliferative response. Factors will be localized with immunocytochemistry and results will direct future work toward immunosuppression of cancer. 4). Cell wall-associated proteins of Streptococcus will be used to study the role of the peptidoglycan matrix on plasmolysis and thus dental plaque. 5). The role of microtubules in mitosis. The mechanism of mitosis is not yet understood, its elucidation has important implications in the understanding of aneuploidy and uncontrolled cell proliferation. Long term goals of the investigators are to be able to use high resolution electron microscopy to augment each research plan.